Abstract
The purpose of this study was to review two surgeons’ medium-term results with the Ascension Pyrotitan surface replacement and the Pyrocarbon hemiarthroplasty. We hypothesized they would provide good medium-term outcomes with no significant difference between the two implants.
The first 21 implants were surface replacements and the subsequent 58 hemiarthroplasties making a total of 79. Overall, the minimum follow-up was two years and maximum nine years and nine months (average = five years and six months). The average follow-up for the Ascension Pyrotitan was eight years and two months and Pyrocarbon hemiarthroplasty was five years and two months. Survivorship, Oxford, and Subjective Shoulder Value (SSV) scores, and incidence of squeaking were recorded. The average age at implantation was 57.7 years (range 20-80). Thirty-five were female and 44 male. The indication for surgery was osteoarthritis in 56 patients, post instability in 10 patients, post fracture in 7 patients, avascular necrosis in 4 patients, synovial osteochondromatosis in one, and rheumatoid arthritis in one.
Of the 79 patients in the cohort, five were deceased, two were revised to reverse for cuff failure, one was revised for Cutibacterium acnes infection, and one was revised to Pyrocarbon hemiarthroplasty for fracture of a Pyrotitan surface replacement. This left 70 patients, all of whom were included in this review. Survivorship at final follow-up for the Pyrotitan surface replacement was 88.9% and Pyrocarbon hemiarthroplasty was 96.4%. The average SSV for all patients reviewed was 86%, the Ascension Pyrotitan patients scoring 87% and the Pyrocarbon hemiarthroplasty scoring 86%. The average Oxford score for the whole cohort was 42 out of a maximum of 48, with Ascension Pyrotitan scoring 42.3 and Pyrocarbon hemiarthroplasty 41.9. Recent Oxford score for the postinstability group was 44, osteoarthritis 42.6, postfracture 39.5, and 35 for avascular necrosis (not statistically significant). Fourteen of 70 patients reported squeaking (20%), 4 daily, 5 weekly, and 5 monthly. Average Oxford score in those who experienced squeaking was 39 compared with nonsqueakers at 43 (P = .02). Correlation between Oxford score and SSV was high with a correlation coefficient of 0.79. The Oxford score for the Pyrotitan at 42.3 was significantly better than the New Zealand Joint Registry score for the Global Cap at 34.5 (P = .001) and the Pyrocarbon hemiarthroplasty at 41.9 significantly better than the Aequalis CoCr hemiarthroplasty at 36.8 (P = .005)
Pyrocarbon looks to be a durable bearing surface and a good option for the younger osteoarthritic patient where risk of glenoid component failure is high.